1. Field of the Invention
The present invention relates to a memory controller, and more particularly to a memory controller that initializes a memory.
2. Description of Related Art
A computer including a main memory is required to be initialized by writing data with a correct ECC (Error Correcting Code) into the main memory during an initialization of the computer. If the main memory is not initialized with the data including the correct ECC, then the data is regarded as invalid data during a check by an ECC check circuit, when read from the main memory. Thus, a memory failure is reported inadvertently.
On the other hand, in recent years, a capacity of a main memory has increased. Further, an initialization time of the main memory has become a large part of the time needed for booting-up the computer. Therefore, the initialization time of the main memory should be shortened to reduce the boot-up time of the computer.
Patent Document 1 discloses a technique for accessing to an external storage device. In the technique, a flag circuit includes a flag corresponding to a memory region of the external storage device. The flag indicates whether data is written in the corresponding memory region. The flag circuit is initialized during a system booting. Therefore, it is confirmed whether the data is written in the memory region or not by setting or resetting the flag.    [Patent Document 1] Japanese Patent Application Laid-Open No. 5-324453.